Determination of acceleration behaviour

Abstract

A method and control unit determines a fuel efficient acceleration behavior of a motor vehicle for a predetermined road section. The determination of the acceleration behavior is based on a determined initial speed of the motor vehicle in a first position in the road section, and a determined target speed of the motor vehicle in a determined second position in the road section, the second position being separated from the first position by an acceleration distance. The first position is determined such that the acceleration distance is less than or equal to a maximal acceleration distance S acc , the maximal acceleration distance S acc being dynamically determined based on at least one first road condition for the road section and on at least one characteristic of the motor vehicle.

The invention claimed is: 
     
       1. A method for determining, setting, and controlling a fuel efficient acceleration behavior of a motor vehicle for a predetermined road section comprising:
 determining an initial speed of said motor vehicle in a first position in said road section, and 
 determining a target speed of said motor vehicle in a determined second position in said road section, wherein said second position is separated from said first position by an acceleration distance; 
 dynamically determining a maximal acceleration distance S acc  based on at least one first road condition for said road section and on at least one characteristic of said motor vehicle and said first position is determined such that said acceleration distance is shorter than or equal to said maximal acceleration distance S acc ; 
 setting said initial and target speeds of said motor vehicle and said acceleration distance of said motor vehicle based on said determined initial and target speeds and acceleration distance; and 
 controlling a speed of said motor vehicle, by a speed altering device of said motor vehicle, so that said motor vehicle reaches said set initial speed at said first position in said road section and reaches said set target speed at said second position in said road section, whereby said motor vehicle travels said set acceleration distance between said first position and said second position. 
 
     
     
       2. The method as claimed in  claim 1 , further comprising performing an acceleration within said acceleration distance, the acceleration having a property that is determined based on at least one second road condition for said road section. 
     
     
       3. The method as claimed in  claim 2 , wherein each of said at least one first and said at least one second road conditions is related to at least one road condition selected from a group consisting of: a topology for at least one part of said road section, at least one desired speed for at least one part of said road section, a straightness of at least one part of said road section, a traffic situation for at least one part of said road section, and a number of vehicles other than said motor vehicle present on at least one part of the road section. 
     
     
       4. The method as claimed in  claim 1 , wherein said at least one characteristic of said motor vehicle is related to revolutions per minute (rpm) and/or a momentum of an engine of said motor vehicle. 
     
     
       5. The method as claimed in  claim 1 , wherein said at least one characteristic of said motor vehicle is related to at least one of motor vehicle specific parameters or features selected from a group consisting of: weight, engine characteristics, air resistance, transmission, brake system, rolling resistance, total gear ratio, inertial forces, and various friction forces of or on the vehicle. 
     
     
       6. The method as claimed in  claim 5 , wherein said maximal acceleration distance S acc  is determined according to: 
       
         
           
             
               
                 
                   s 
                   acc 
                 
                 = 
                 
                   
                     
                       ∫ 
                       
                         v 
                         initial 
                       
                     
                     
                       v 
                       target 
                     
                   
                   ⁢ 
                   
                     ∫ 
                     
                       
                         
                           
                             F 
                             sum 
                           
                           ⁡ 
                           
                             ( 
                             s 
                             ) 
                           
                         
                         
                           vm 
                           t 
                         
                       
                       ⁢ 
                       
                         ⅆ 
                         s 
                       
                     
                   
                 
               
               , 
             
           
         
       
       where
     F   sum   =F   engine (η max )− F   brake   −F   airdrag (ν)− F   roll (α)− F   gravity (α),
 
 
       where
 F engine (η max ) is a net engine force, 
 F airdrag (ν) is a force caused by the air resistance of the motor vehicle, 
 F roll (α) is a force caused by the rolling resistance, 
 F gravity (α) is a force of gravity, 
 α is an incline of the road, 
 ν initial  is the initial speed for the motor vehicle in the first position, 
 ν target  is the target speed for the motor vehicle in the second position, 
 m t  is a total dynamic vehicle mass, and 
 ν is the speed of the motor vehicle. 
 
     
     
       7. The method as claimed in  claim 1 , wherein said maximal acceleration distance S acc  is also determined based on at least one input from a driver of said motor vehicle. 
     
     
       8. The method as claimed in  claim 7 , wherein said driver input is chosen according to any value selected from a group consisting of: a value corresponding to an arbitrary maximal acceleration distance S acc ; a value corresponding to one adjustment coefficient in a set of predefined adjustment coefficients, wherein said predefined adjustment coefficients are to be multiplied by said maximal acceleration distance S acc ; and a value corresponding to a speed change dependent maximal acceleration distance S acc . 
     
     
       9. The method as claimed in  claim 8 , wherein said speed change dependent maximal acceleration distance S acc  is dependent on an actual location on said road section where an acceleration is to be performed. 
     
     
       10. The method as claimed in  claim 7 , wherein said maximal acceleration distance S acc  is determined such that said input by a driver of said vehicle is perceived as resembling an acceleration on a level road. 
     
     
       11. The method as claimed in  claim 1 , wherein a length of said predetermined road section is adjustable. 
     
     
       12. A computer program recorded on a non-transitory computer readable medium, which is run in a control unit of a motor vehicle, the program being configured to cause the control unit to execute the method according to  claim 1 . 
     
     
       13. A computer program product including a non-transitory computer readable medium and a computer program according to  claim 12 . 
     
     
       14. A computer program product according to  claim 13 , wherein said non-transitory computer readable medium consists of one or more devices selected from the group consisting of: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), Flash memory, and EEPROM (Electrically Erasable PROM). 
     
     
       15. A control unit for determining a fuel efficient acceleration behavior of a motor vehicle for a predetermined road section, said control unit including:
 a determination apparatus configured and operable for determining said acceleration behaviour based on: 
 a determined initial speed of said motor vehicle in a first position in said road section; and 
 a determined target speed of said motor vehicle in a determined second position in said road section, said second position being separated from said first position by an acceleration distance; 
 said control unit further including a first device configured and operable for determining said first position such that said acceleration distance is shorter than or equal to a maximal acceleration distance S acc ; and 
 a second device for dynamically determining said maximal acceleration distance S acc  based on at least one first road condition of said road section and on at least one characteristic of said motor vehicle. 
 
     
     
       16. The control unit as claimed in  claim 15 , wherein said control unit further includes a third device configured and operable for determining a property of an acceleration to be performed within said acceleration distance based on at least one second road condition for said road section. 
     
     
       17. The control unit as claimed in  claim 15 , wherein said second device for dynamically determining said maximal acceleration distance S acc  is connected at least to a reception device configured and operable for receiving:
 positioning information concerning said vehicle; 
 electronic map information; 
 information related to said at least one road condition; and 
 information related to said at least one characteristic of said motor vehicle. 
 
     
     
       18. The control unit as claimed in  claim 17 , wherein said reception device is also configured and operable for receiving at least one input from a driver of said motor vehicle. 
     
     
       19. The control unit as claimed in  claim 18 , wherein said reception device is also configured and operable to receive one type of input selected from the group consisting of: a value corresponding to an arbitrary maximal acceleration distance S acc , and a value corresponding to one adjustment coefficient in a set of predefined adjustment coefficients, said one adjustment coefficient to be multiplied by said maximal acceleration distance S acc . 
     
     
       20. The control unit as claimed in  claim 15 , wherein said control unit further includes adjustment means arranged for adjusting a length of said predetermined road section. 
     
     
       21. A system for an automated speed control of a motor vehicle, comprising:
 the control unit as claimed in  claim 15 ; and 
 a speed altering device of said motor vehicle configured and operable so as to be controlled by said control unit.